The official Xinhua news agency reported that the accident occurred in the regional capital of Urumqi on Oct. 24 when 33 workers were underground, the report said citing local officials.

Eleven workers were injured and six escaped, it added.

The report did not identify the name of the coal mine and said the cause of the accident is being investigated.

China's mines are the deadliest in the world because of lax enforcement of safety standards and a rush to feed demand from a robust economy. Twenty two workers were killed in a coal mine accident in southwestern China in June, Reuters reported.

In an effort to eliminate outdated capacity and improve work safety, China plans to shut down over 2,000 small-scale coal mines by 2015.